That's not true. Who taught you that nonsense?
Therefore I say to you, any sin and blasphemy shall be forgiven people, but blasphemy against the Spirit shall not be forgiven. — Matthew 12:31The context of blasphemy against the Hagios Pneumos is in the letter to the Hebrews:
Truly I say to you, all sins shall be forgiven the sons of men, and whatever blasphemies they utter; / but whoever blasphemes against the Holy Spirit never has forgiveness, but is guilty of an eternal sin … Mark 3:28-29
For if we go on sinning willfully after receiving the knowledge of the truth, there no longer remains a sacrifice for sins, / but a terrifying expectation of judgment and THE FURY OF A FIRE WHICH WILL CONSUME THE ADVERSARIES. / Anyone who has set aside the Law of Moses dies without mercy on the testimony of two or three witnesses. / How much severer punishment do you think he will deserve who has trampled under foot the Son of God, and has regarded as unclean the blood of the covenant by which he was sanctified, and has insulted the Spirit of grace? / For we know Him who said, “VENGEANCE IS MINE, I WILL REPAY.” And again, “THE LORD WILL JUDGE HIS PEOPLE.” / It is a terrifying thing to fall into the hands of the living God. — Hebrews 10:26-31On top of that, Jesus has deliberately blinded a great deal of humanity for His purposes:
HE HAS BLINDED THEIR EYES AND HE HARDENED THEIR HEART, SO THAT THEY WOULD NOT SEE WITH THEIR EYES AND PERCEIVE WITH THEIR HEART, AND BE CONVERTED AND I HEAL THEM. — John 12:40, referencing Isaiah 6:10